use Test::More tests => 5; use Graph; my $g = Graph->new; ok( $g->add_edge("a", "b") ); ok( $g->add_edge("b", "c") ); is( $g->add_edge("c", "d"), $g ); eval '$g->add_edge("c", "d", "e", "f")'; like($@, qr/Graph::add_edge: graph is not hyperedged/); eval '$g->add_edge("c")'; like($@, qr/Graph::add_edge: graph is not hyperedged/);